With her Micronesia passport apply for the multi-entry tourist visa. That can only be applied for in your passport country. That will give her almost a full 9 months in Thailand with only two border bounces, and three extensions. That is the easiest way to start, and the overstay makes no difference.
with your teaching history you are in demand at the top international schools. You will need a certified as being real copy of your university diploma, and teaching certificate, in order to get your work permit. Ajarn.com spells it all out, with job openings. With your experience you can easily make over bt80,000+ a month teaching full time. The only strict retirement age is working in the government, and that is 60, with legislation in the works to raise that to 65, but might not be done anytime soon. At the university level teaching business English is in demand at a number of universities with international business programs. With your experience, with references, you are in the top ranks of new hires, with very little competition.
rejoice in your idealism. Thailand doesn't really care. You seem to think Thailand needs money, without realizing Thailand is the second largest economy in South East Asia, and very profitable.
The embassies don't care how much you make, only, if they ask, that you are making money, and paying your taxes on the money you make, if they ask. Basically you can't be a freelancer working for free, if they ask, and they have been asking a lot more lately.
Anonymous participant never forget, on a DTV you are just a tourist, no matter how long you stay in the country. On everything you buy there is tax, and VAT, that pays for all the services you use. Your idealism is commendable, but you are missing a lot of what you actually pay for what you use, at about 17% of what you actually spend daily.
Anonymous participant technically you are doing business, and making money, in Thailand, not remotely, which is a violation of the visa. You should also be paying income tax on the money you make from the Airbnb.